I used this product for only two weeks. It did have immediate effects in reducing my desire for food. I felt full and also had increased energy. I was actually able to only drink one of these a day and the effects lasted throughout the entire day. The reason I stopped using this is because it also caused to to not sleep well at night, which is something I rarely ever have a problem with. Some nights I would lay awake in bed until 2 am, others I would sleep fitfully, waking up periodically through the night. Within a couple days of discontinuing use, my sleeping patterns returned to normal. It is possible that I was hyper sensitive to the effects of this product, given that just one would last me all day. If this is the case, this product would still be beneficial to other users. I would suggest trying a few individual samples of this product before purchasing an entire box. My sleeplessness began immediately, so that should be enough to determine whether you are similarly affected.